BOSTON – It may be hard to remember now, but there was a time when Derek Jeter wasn’t the captain of the Yankees. There was a time, in fact, when the naming of Jeter as the 11th captain in team history was thought to be a curious maneuver. This was back in June 2003, back when it seemed George Steinbrenner and Joe Torre were engaged in a terminal Cold War.

Jeter’s ascent in Cincinnati’s Great American Ballpark was seen in some precincts that day as some kind of cheap motivational stunt, both for the shortstop who’d been branded a party hound some months earlier, and for the manager who was seen to be playing out the string of the final Yankees contract he expected to work under.

Now, almost 17 months later, that all seems so comical.

Now, in the aftermath of the most discouraging Yankees October since 1955 (and don’t for one second think Yankees fans didn’t take the end of their personal dominance over the Dodgers as poorly and as personally as they now take a similar shift in their relationship with the Red Sox), Jeter’s value and importance to the club have never been greater, both on the field and in the clubhouse.

You can start on the field, because that may be where the most shocking transformation took place. When last year ended, there were still many people who believed Jeter was the fourth-best shortstop in the American League. Twelve months later, he is the winner in an epic landslide. You have one candidate (Alex Rodriguez) who isn’t even a shortstop anymore, another (Nomar Garciaparra) who isn’t even in the league anymore, and a third (Miguel Tejada) who apparently went to Baltimore and entered the Federal Shortstop Protection Program, for all anyone heard from him this year.

“Anyone who ever questions what kind of level this kid plays his position at, they were crazy then but they’re crazier now,” is the way Joe Torre termed it during the Yankees’ abbreviated stay in the postseason. “This time of year, you have a lot of guys who might secretly think to themselves, ‘Please, God, don’t let them hit it at me.’ Jeter says, ‘Hit every damned ball my way, go ahead.’ ”

But at this seminal moment in Yankees history, the Yankees need Jeter even more for what else he brings to the job of captain. Forget the usual duties and the usual clichés that always tumble from a captain’s lips (including this one’s): leadership, responsibility, accountability, yadda, yadda, yadda.

No, Jeter brings to the job of Yankees captain a talent that is unique and specific to the job of Yankees captain. He brings exacting standards and an unwillingness to suffer fools, or underachieving teammates, lightly. Those who choose to despise the Yankees may see this as the arrogance of a player who enjoyed four championships in his first five years as a major leaguer, and maybe some of that applies.

More likely, it is the product of one of the few Yankees who have played for George Steinbrenner under baseball’s modern fiscal truths who completely and utterly get what it is to play for the Yankees, and to accept the checks that Steinbrenner writes every 1st and 15th. He accepts the rule that says if you’re going to get paid like a champion twice a month, you’d better play like one the other 28 or 29 days.

Especially in the 10th month.

“The standards here are different, that’s all,” Jeter said as wave after wave of notebooks and microphones and klieg lights assaulted him in the wee hours of Wednesday morning, after suffering through the worst humiliation of his career. “We know what we’re expected to do. Yes, they’re tough. But I wouldn’t want to play if it was acceptable to finish second every year.”

Trite? Maybe. Predictable? Yes. Straight out of the captain’s training manual? Sure. But you know something? Jeter’s greatest strength as a captain will never come out of his mouth, even if he’s never once taken refuge in the trainer’s room after even the most sickening loss. It’s how he acts on the field. It’s how he demands others act.

Time was, Jeter wouldn’t be quite as needed around here. Time was, the Yankees had plenty of key players who subscribed to the same belief system. Slowly, they have almost all gone away. Bernie Williams remains, maybe half the player he used to be. Jorge Posada seems to age by the at-bat. And as good as Mariano Rivera still is, there is only so much leadership to be done by a man who participates in fewer than 80 innings per year.

So it’s all on Jeter. For now, and for the foreseeable future. On some teams, the job of captain is an honoraria. On this team, at one time, it would have been a silly indulgence. But on this team, at this point in their history, there has never been a greater need for the skills Jeter possesses in abundance.

On the field. Off the field.

Everywhere.

Mike Vaccaro’s e-mail address is WriteBackVac@aol.com.

VAC’S WHACKS

What’s the over-under for the dissolution of the Stephon Marbury-New York City honeymoon? Does it at least make it past the home opener?

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Say what you will about New York City, but we somehow manage to celebrate championships around here every few years without someone getting maimed. Or killed. Jimmy Kimmel found a lot of trouble a few months ago when he said about Detroit what everyone else believes about every other city about to welcome a championship: Watch yourself. Boston early Wednesday morning only confirmed those awful fears.

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Chad Pennington already has gone a long way toward planting himself in the role as New York’s next superhero in spikes. If he could ever help the Jets steal one in Foxboro today, he might actually start inching his way toward Jeterville.

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He’s been a good enough guy during those times he’s been healthy in New York, so for that reason alone you can wish a full recovery for Jason Giambi. But you also have to say this: Right now, he sure is the leader in the clubhouse for the worst free-agent signing in the history of free-market sports. And he hasn’t even started to collect the fattest chunk of his back-loaded contract yet.